1. Field of the Invention
The present invention relates to ink jet printing apparatuses, and relates in particular to the determination of the ink tank mounting state.
2. Description of the Related Art
As for ink jet type printing apparatuses such as ink jet printers and the like, techniques are known that determine the mounted state of the respective ink tanks by way of using a line that is common to multiple ink tanks mounted on a carriage (a so-called bus connection wiring) (Japanese Patent Laid-Open Nos. 2002-370378, 2004-058645). The checking of whether ink tanks are mounted/not yet mounted by way of using identification information corresponding to the ink colors stored in the ink tanks is described in these documents.
As for an ink tank mounting determination structure using the aforementioned bus connection wiring, it is further preferable that it be capable of determining whether or not multiple ink tanks of the same color are mistakenly mounted. By being able to make this type of determination, for example, it is possible to notify the user of the case that the ink tanks are incorrectly mounted, and it is possible to notify the user of the ink tank that should be removed. Thereby, it is possible to improve the usability of the apparatus.
In the following manner, for example, it is possible to determine whether multiple ink tanks of the same color are mistakenly mounted, in a configuration using a bus connection wiring. This determination method will be explained by making use of FIG. 19 and FIG. 20. FIG. 19 and FIG. 20 illustrate a printing apparatus using ink tanks totaling four colors; cyan (C) magenta (M), yellow (Y) and black (K). A mounting unit of C, M, Y and K ink tanks, electrical contacts provided on the respective mounts, a common wiring electrically connected in common with these electrical contacts, and a control circuit that performs determinations such as those explained below by sending information (data, signals) to the common wiring and receiving information through the common wiring, are provided on the printing apparatus main body side. On the other hand, control circuits and electrical contacts are provided on the ink tank side. In a state where the ink tanks are mounted in the ink tank mounts (mounting portions), the tank side control circuits and the main body side control circuit electrically connect via the electrical contacts, and herewith both (the tank side control circuits and the main body side control circuit) become capable of information communication. Thus, as explained below, by performing the transfer of color ID (color identification information) and individual tank number information between both of them, it is possible to check whether ink tanks of the same color are mistakenly mounted. It should be noted that FIG. 19 illustrates a case where four colored (CMYK) ink tanks are mounted normally and FIG. 20 illustrates a case where two C ink tanks have been mistakenly mounted.
First, stored identification information corresponding to the ink colors (hereinafter also referred to as color ID) is sent from the main body side control circuit of the printing apparatus, through the common wiring, to (the control circuits (also referred to hereinafter as ink tank side control circuits) of) the ink tanks. Next, each of the tank side control circuits compares the received color ID to the color ID stored in its own memory, and in the case where there is color ID agreement returns that color ID to the main body side control circuit. For example, in the case where the main body side control circuit has sent a Y-ID, each of the C, M, Y and K ink tanks receive the Y-ID, but because among these only the Y ink tank has color ID agreement, only the control circuit of the Y ink tank returns a Y-ID to the main body side control circuit. Next, the main body side control circuit confirms the mounting of the ink tank based on the received color ID. Here, the main body side control circuit, in the case where color IDs of all of the ink tanks that should be mounted are received, determines that ink tanks of all of the colors are mounted. For example, in the case of FIG. 19, C, M, Y and K color IDs are sequentially sent from the C, M, Y, and K ink tanks to the main body side control circuit, and because the main body side control circuit receives color IDs of four colors, it can confirm the existence of ink tanks of four colors. On the other hand, in the case where, among the ink tanks that should be mounted, there is a color ID of an ink tank whose mounting can not be confirmed, that is, in the case where there is a color ID insufficiency of the ink tanks that should be mounted, an individual tank number checking processing is subsequently performed. For example, in the case of FIG. 20, an M-ID is not sent from the ink tank side to the main body side control circuit because an M ink tank is not mounted. Thus, because the main body side control circuit did not receive an M-ID it determines that there is a color ID insufficiency and transitions over to the individual tank number checking processing.
In the individual ink tank number checking processing, the main body side control circuit requests, from the tank side control circuit of each of the ink tanks whose color ID was confirmed, its individual tank numbers stored in its memory at the time that ink tank is manufactured. In response to this request, the tank side control circuit sends response signal that express the individual tank number stored in its memory to the main body side control circuit. Next, the main body side control circuit sends the received individual tank number to the ink tanks via the common wiring. In response to this, the tank side control circuits returns a response signal (the individual tank number) to the main body side control circuit in the case where there is agreement between the individual tank number sent from the main body side control circuit and the individual tank number stored in its own memory, and does not send a response signal in the case where there is not agreement.
Here, the main body side control circuit, in the case where individual tank numbers can be checked with respect to all of the confirmed color IDs (the presence of response signals), determines that the ink tank of the aforementioned insufficient color ID is not mounted (not yet mounted). On the other hand, the main body side control circuit, in the case where an individual tank number can not be checked for one of the ink tanks confirmed by color ID (the absence of a response signal), determines that a plurality of ink tanks of that color ID are mounted. For example, in the case of FIG. 20, as explained below using FIG. 1, the main body side control circuit determines that a plurality of C ink tanks are mounted because it can not confirm the individual tank number of the C tank 1 and C tank 2, confirmed by the C-ID.
FIG. 1 is a diagram explaining the above described individual tank number checking processing, which illustrates the response signals (individual tank number) output by the tank side control circuits of the respective ink tanks, and illustrates the obtained detection signal by that the main body side control circuit detects the response signals. More concretely, as an example, respective response signals and detected signal are shown for the case where two cyan ink tanks (C tank 1, C tank 2) are mounted. In FIG. 1 the individual tank number of C tank 1 is “01011010” and the individual tank number of C tank 2 is “01101011”.
Thus, as described above, when the main body side control circuit requests an individual tank number by the cyan color ID, C tank 1 outputs a “01011010” individual tank number response signal and c tank 2 outputs a “01101011” individual tank number response signal. As a result of this, the main body side control circuit detects the signal shown in FIG. 1, which is formed from the so-called collision of the response signals from the two tanks. Here, usually, each of the sections of which the response signal is composed is at either a high or low voltage, but at the time when multiple response signals collide, in the case where the response signal from one of the tank side control circuits is high and the response signal from the other tank side control circuit is low, it becomes a voltage that is between them. At the corresponding section in the example signal shown in the figure, the intermediate voltage of the signal formed by the collision is 1.5V, half of 3.0V and 0V. Thus, in the case where a detection threshold value of the main body side control circuit is 1.3V, the main body side control circuit recognizes that the individual tank number of the signal obtained by the request is “01111011”. Next, the main body side control circuit sends the individual tank number recognized as set forth above to the ink tanks having a cyan color ID and requests a response from the respective tanks according to whether or not there is individual tank number agreement. Neither of C tank 1 or C tank 2 responds to this because their individual tank numbers do not agree. As a result, the main body side control can determine that multiple ink tanks of the same color are mounted. It should be noted that the case in which individual tank numbers agree and there is a response of the agreement is the case where the individual tank number of the response signal requested and obtained is a signal wherein multiple response signals have not collided. That is, it is the case where, with respect to one color ID, an individual tank number has been sent from one ink tank. In this case, in the case where there is a color ID insufficiency, that is, in the case where all of the ink tanks that should be mounted are not mounted, it is possible to determine that the ink tank of the insufficient color ID is not yet mounted.
As explained above, in a structure using a bus connection wiring, it is possible to determine whether or not multiple ink tanks of the same color are mounted. However, there are cases where the intermediate voltage value of the response signal (detected signal) composed by a collision of multiple response signals is not always a constant value due to individual differences such as, for example, the production lots of the multiple tank side control circuits differing. In this case, there are occasions where the signal detected by the main body side control circuit, when multiple response signals from the tank side control circuits have collided, undesirably expresses the individual tank number of an ink tank. Also, there are occasions where the threshold value used by the main body side control circuit varies, albeit slightly, due to the characteristics of the electric circuit or value of the wire resistance. In this case, there are occasions where the threshold value undesirably differs according to individual differences such as the aforementioned circuit characteristics. Also in this case, in the same manner, there are occasions where the signal detected by the main body side control circuit, when multiple response signals from the tank side control circuits have collided, undesirably expresses the individual tank number of an ink tank in spite of the collision of response signals.
FIG. 2 and FIG. 3 are diagrams explaining such signal detection, and are similar to FIG. 1. FIG. 2 illustrates a case where the tank side control circuit characteristic difference between C tank 1 and C tank 2 is comparatively large. More specifically, due to the response signal from the tank side control circuit of C tank 1 with a comparatively high output impedance and the response signal from the tank side control circuit of C tank 2 with a comparatively low output impedance, the intermediate voltage of the signal detected when these collide becomes 1.7V or 1.3V according to the highs and lows of the respective signals. At this time, in the case where the main body side control circuit threshold value is the same 1.3V as the example of FIG. 1, the individual tank number acquired by the main body side control circuit becomes “01011010”. This individual tank number is the same as the individual tank number of C tank 1 and thus individual tank numbers end up agreeing. As a result of this, in spite of the fact that multiple ink tanks of the same color ID are mounted, it is determined that the ink tank of the insufficient color ID is not yet mounted. For example, in the case of FIG. 20 described above, in spite of the fact that multiple C ink tanks are mounted, it is determined that the M ink tank is not yet mounted without determining that multiple C ink tanks are mounted. This determined result is certainly not wrong because it is a fact that the M ink tank is not yet mounted. However, because multiple C ink tanks are mounted, it is preferable to increase determination accuracy such that this mounting state can be detected. Also, usability would be improved if it were possible to notify the user with a multiple ink tank mounting error and a tank not yet mounted error distinctively.
FIG. 3 illustrates a case where main body side control circuit characteristics of printing apparatus main bodies differ, and the threshold value, when detecting response signals, undesirably differs in accordance therewith. More specifically, in the case where the intermediate voltage of the signal detected when there is a collision of response signals becomes the same 1.3V or 1.7V as the example shown in FIG. 2, a case is shown where the threshold value is not 1.3V but rather 1.6V due to the characteristics of the main body side control circuit that detects the response signal. In this case as well, the individual tank number acquired by the main body side control circuit becomes “01011010”. This individual tank number becomes the same individual tank number as C tank 1, and in spite of the fact that multiple ink tanks of the same color are mounted, it ends up being determined that the ink tank of the insufficient color ID is not yet mounted, due to individual tank number agreement.
In this way, the method of determining whether multiple ink tanks of the same color are mounted, described at FIG. 1, has a problem wherein the determination accuracy is decreased due to differences among tank side control circuits and the characteristics of main body side control circuits.